A suspended ceiling of the type noted above has spaced frame members, each having an upwardly projecting rail with an upper portion that is wider when compared with a lower portion of the rail. A hanger, which is stamped from sheet metal and which is useful for hanging an electrical fixture from a suspended ceiling of the type noted above, is exemplified in Williams U.S. Pat. No. 4,114,327.
As disclosed in the Williams patent, a pair of such hangers are used with suitable mounting brackets to hang an electrical fixture, such as a light fixture, a speaker box, a fire alarm box, or an exit sign from a suspended ceiling. Similar hangers are available commercially from S-P Products, Inc. of Elk Grove Village, Ill., under its trade designation "EZ Bar Hanger System".
Generally, the hanger has a main panel, an upper flange, and a lower flange and is provided near each of its opposite ends with a slot defining a tab. The slot, which opens at a projecting edge of the lower flange, extends through the lower flange, into the main body, and is adapted to accommodate the upper portion of the upwardly projecting rail of a frame member of a suspended ceiling. The tab, which extends to the projecting edge of the lower flange and to a nearer one of the opposite ends of the hanger, comprises a portion of the main panel and a portion of the lower flange and is shaped so as to lock the hanger to the upwardly projecting rail of the frame member. The slots are spaced equally from the opposite ends of the hanger.
Generally, when one of the commercially available hangers mentioned above is installed so as to coact with two frame members of a suspended ceiling, it is necessary for an installer to bend the tabs upwardly from their normal positions, so as to allow the upper portions of the frame members to enter the slots. Generally, moreover, it is necessary for the installer to bend the tabs back approximately to their normal positions so as to lock the hanger to the frame members after the slots have received the upper portions of the frame members.
Commonly, when one of the commercially available hangers mentioned above is installed, it is necessary for the installer to measure a centerline between the opposite ends of the hanger and to mark the centerline, as by means of a crayon, so that an electrical fixture being hung by means of the hanger can be readily centered between the frame members coacting with the hanger.
Measuring and marking a centerline can require from thirty seconds to one minute or more of an installer's time, which may be quite expensive for an electrical contractor having to charge one dollar (U.S. $1.00) or more for each minute of the installer's time, particularly on a large-scale job involving many repetitive installations of similar hangers.